8.2.3. More advanced settings
The tool "ip" is less documentated, but very strong. See online "help" for more:
# ip -6 neigh help
Usage: ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] 
          [ nud { permanent | noarp | stale | reachable } ] 
          | proxy ADDR } [ dev DEV ] 
       ip neigh {show|flush} [ to PREFIX ] [ dev DEV ] [ nud STATE ] | 
Looks like some options are only for IPv4...if you can contribute information about flags and advanced usage, pls. send.